Long-Term Administration of Glycerides Rich in Conjugated Linoleic Acid (CLA) to Diabetic C57BLKS-Lepr^db/lepr^db Mice

Abstract

Conjugated linoleic acid (CLA) is reported to display anti-diabetic activity in Zucker diabetic fatty fa/fa rats, but to induce insulin resistance in various other animal species. CLA was administered to diabetic C57BLKS-Lepr^db/lepr^db (db/db) mice long-term and its influence on diabetic symptoms was examined in this animal model. In addition, triacylglycerol CLA (TG-CLA), enzymatically prepared to provide organoleptic satisfaction, was used. Mice were fed for 23 weeks one of three diets supplemented with 1.2% safflower oil (control), 0.53% TG-CLA and 0.67% safflower oil (TG-CLA (L)) or 1.2% TG-CLA (TG-CLA (H)). During the administration, food intake did not differ between the groups. Body weight was significantly lower in the TG-CLA (H) group than in the control group (P<0.001). The body weight of the TG-CLA (L) group was between those of the other two groups. The abdominal and epididymal fat pad weight of the TG-CLA (H) group was reduced compared to the control (P<0.05). Plasma glucose and insulin levels were not affected by the TG-CLA supplementation. Serum triglyceride levels were noticeably reduced in mice fed TG-CLA compared to those fed the control diet (P<0.01) at certain stages of the administration (from 10 to 14-weeks of age). The serum GPT level of the TG-CLA (H) group was much higher than that of the control (P<0.05). The histopathological evaluation of the liver, the kidney and the pancreas revealed no effect of TG-CLA administration on these tissues. Consequently, long-term administration of TG-CLA has no adverse effect on the diabetic status in diabetic db/db mice.